1. Field
Example embodiments relate to a nanotube based nonvolatile memory device and a method of fabricating and operating the same. Other example embodiments relate to a nonvolatile memory device using a bistable switching structure of a nanotube and a method of fabricating and operating the same.
2. Description of the Related Art
Examples of conventional memory devices include random access memories (RAMs), read only memories (ROMs), static random access memories (SRAMs) and/or magnetic random access memories (MRAMs). These semiconductor memory devices may be generally classified into volatile memory devices and nonvolatile memory devices, which have their own advantages and disadvantages. The fields of application for the semiconductor memory devices may be different.
In order to overcome the disadvantages of the conventional semiconductor memory devices and explore new fields of application, there is a demand for developing new memory devices. It is generally known that nonvolatile memory devices may operate slower than volatile memory devices. Research is being conducted into memory devices that may combine the advantages of both volatile memory devices and nonvolatile memory devices and that may be applied to a wider range of fields than conventional memory devices. For example, nanotube based memory devices are being researched and publicly reported.
The conventional art may suggest a nonvolatile memory device using a carbon nanotube (CNT) ribbon. However, the conventional nonvolatile memory device may be a write-once read-many (WORM) memory device, which is not suitable for a dynamic storage device. The conventional art may suggest a nonvolatile memory device using a set of parallel CNTs. The conventional nonvolatile memory device may create an ON state by deforming the facing CNTs while applying an electrical field and an OFF state by grounding and restoring the deformed CNTs. However, each nonvolatile memory device may require two CNTs and an appropriate distance may be maintained between the two CNTs. A support device for charging a space between the CNTs with an appropriate electrical potential may be required for the deformation of the CNTs, e.g., for memory retention.